CAD Axle violent release.

[Mopar1973Man]

I didn't think 2001.5's had CAD? Or are you talking release the transfer case? I will also use 4wd for braking, it's one more thing keeping the tires from locking.

If the transfer case is locked into 4wd then if one driveshaft is spinning then the other one has to be as well. This means that if both front or rear tires were to hit a slick spot and try to lock up then at least one tire on the opposite axle would have to stop as well, if the opposite axle has traction at least one tire won't lock up. Every 4wd rig I have owned stops/stopped better on snow/ice when in 4wd than 2wd. Even my wifes 4Runner has noticeably better braking in AWD than 2wd.

Very true. Like coming down a slick dirt road 4WD will help in keeping the the axle from sliding. But once it does start to slide its really tough to recover the traction again if you have long stretches of ice/snow covered roads. I've also notice the same thing on ATV's the tend to follow this rule as well. Another thing make sure your exhaust brake is off that a great way to get a 4 wheel slide started just hit the exhaust brake and she'll start to glide on you. As for the CAD unit. Wasn't much wrong with it. It had been stuck by road debris and bent the vacuum diaphragm can so it would pull fine to engage 4WD but had troubles returning to 2WD. Vacuum was at both ports as selected. But since the can was bent it was binding the rod slightly. So I removed the CAD unit and took it over to the work bench to pop the E clips out to remove the vacuum diaphragm unit for straightening. First clip. No problem. Second clip! Ting. Tap. Tang. $__T! Damn thing went flying across the shop never found it. 3rd one was easy after the one flew. So using my table vise I clamped to the base hex and was lightly prying up with a screw driver straightening the shaft side of the vacuum diaphragm. Got it just about perfect again. So off to Riggins, ID to get a 22 cent E clip. (Grrrr!) Ok. But get back home and assembly it back together and it works good. CAD unit locks and unlocks just fine now but the transfer case is a bit slow to release. So if I pause along the road and shift either to 4WD to 2WD it will engage/disengage just fine but rolling it will unlock the CAD but hold the front shaft turning till I stop.

[AH64ID]

Cheap fixes are the best! Glad it was something simple.

[dennhop]

One thing while we're on the subject of the CAD that I found out years ago with my 98 1500, a lot of times if it's doing one or the other (engaging/disengaging) but not both, is one of the vacuum lines will tend to break somewhere up the line-very inconvenient as you never seem to find out till you actually need it.  What I did with mine since I found out the line broke while I was out playing around, was take the connector on the back of the CAD and flip it around-as long as you have good vacuum in one line, you can use that same line to suck the diaphragm back into place-whether it's 4wd or 2wd. All you have to do is ensure the shift lever is in the proper place for the vacuum line-ie if your 4wd vacuum line is broken, to get back to 2wd, you leave it in 4wd and flip the vacuum connector, and vice versa for 2wd.  

 

It's never a bad thing to periodically inspect the CAD, as Mike found out, because like others have said, it tends to collect moisture and then cause the diaphragm to rust and freeze up in there (I know that wasn't Mike's issue, but it's a common issue). 

 

Sorry for the lack of posting, I've been pretty busy, as I'm now back in Indiana.  Had to pack up and move from NC back to IN in about a week, and start hunting for a new job-due to 3 surgeries on my ankle, and it not healing properly, the Marine Corps decided I was no longer fit for duty, and medically separated me.  Been pretty busy with everything lately!  Mike, please don't delete my profile if I'm not on for a few months...once everything settles down and I find a job, I'll be a regular on here again!  

[diesel4life]

Good point dennhop, Ive actually done that before in a pinch to get 4 whl drive, I was stuck in a snow drift when I realized I had a vaccum issue. It took a little digging to get under the truck, but a quick swap of the lines was all it took (and a little coaxing forward to reverse) and she went right in. After that I replaced all the lines from the t case to the actuator, hard lines included, to avoid any future problems.Good luck in the job search, I hope you are able to get back on your feet soon.

[Ilikeoldfords]

Well, just found a broken vacuum line going to the infamous CAD unit on the truck. Where is a good place to find replacement vacuum lines? Or should I just replace them with regular rubber lines? I would really like to keep the stock style lines if possible.

[diesel4life]

I used brake line for the steel section. Remove the old line and measure and bend the new line to match. If you buy that copper/nickel alloy stuff you can make sharp bends by hand it's so easy to work with. And lasts a lifetime, will not corrode like standard brake line will. That is all I use anytime I have to replace a brake line because I know I will never have to worry about it again.

[Ilikeoldfords]

The steel lines are ok, its the molded plastic tubing that got brittle and broke in a couple of spots. Does anyone but the dealer sell those molded plastic lines with the rubber ends?

[mopartechnician]

Rubber hose is fine

[rancherman]

I  had  quite  a  'bang'  upon  going into    2wd  last fall.   Sometimes  it  would  take   several miles  for the light go out,     then BANG.   I just  started  backing up a few feet  to  speed up the process.   2-3 foot  is  all it takes.

 

Nothing wrong  with  the  servo.  or  lines.

 

It  was  the  tires.     Soon as  I  replaced  all  6,  it  shifted  smooth  and  quickly...     quarter  inch difference  in  'wear'  makes  quite  a  difference in  ratios  front to rear...

 

. a  sticky/bad/leaking  servo won't make it go  'bang'...  only   extreme  torsional  differences...   

[Ilikeoldfords]

Well I went ahead and just replaced the molded plastic lines with regular rubber lines. Shifts in and out of 4WD instantly now. Thanks for the replies everyone!!

[Mopar1973Man]

I might have to look into that.